JPH0881790A - Plasma-inert cover and method and apparatus for plasma cleaning by using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cleaning method for a hermetic space, such as a vacuum deposition chamber, which shortens an indirect time and avoids the formation of the detrimental deposits on the element in the hermetic space, such as heater plate, in the vacuum deposition chamber.

SOLUTION: The method for removing deposits from the inside of a space at least partly segmented by the surface to be subjected to attack from a plasma includes the steps of placing a cover including a material inert to the plasma on its surface and removing the deposits. As a result, the rapid cleaning of the hermetic space is made possible.

COPYRIGHT: (C)1996,JPO

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates to processing materials such as semiconductor wafers in enclosed spaces such as vacuum deposition chambers. More particularly, the present invention relates to an improved cleaning method for removing deposits such as tungsten or tungsten silicide deposits from vacuum deposition chambers.

[0002]

2. Description of the Prior Art In the processing of semiconductor wafers to form integrated circuit structures, blanket deposition followed by etching or chemical mechanical polishing, or by patterning to expose the silicon or aluminum surface to which tungsten is selectively deposited. It is desirable to deposit a material such as tungsten on the wafer by chemical vapor deposition (CVD) by selectively depositing tungsten on a mask layer such as an oxide layer.

In any case, deposits of materials such as tungsten are usually deposited in a vacuum deposition chamber, eg,
Accumulation on the exposed surface of the heating plate and the susceptor (a table or a support other than the surface of the heating plate on which the semiconductor wafer is mounted during deposition) in the chamber. Such deposits tend to change the dimensions of the chamber and peel off exposed surfaces onto the wafer being processed in the chamber, and chemically change the deposition environment, especially for subsequent selective deposition processes. , Must be removed periodically. The CVD process is significantly affected by such changes.

Previously, plasma assisted etching (plasma)
It has been customary to remove such deposits using a-assisted etch), especially fluorine etching. A source of fluorine gas is supplied to the vacuum deposition chamber, and then a showerhead that supplies gas to the vacuum deposition chamber during deposition is connected to the RF source to generate plasma in the chamber during gas flow. The heater plate, susceptor or other surface on which the wafer during deposition is normally mounted is grounded. Fluorine reacts with deposits such as tungsten or tungsten silicide and the resulting gaseous reaction products are removed from the chamber by a vacuum pump. Such a method sufficiently removes tungsten or other deposits from the susceptor in the vacuum chamber.

Chang, US Pat. No. 5,207,836, discloses an improved cleaning method. The Chang method continues to provide the step of flowing a hydrogen gas source through the chamber while maintaining the plasma in the chamber. This additional step removes any fluorine residue remaining in the chamber, thus preventing such residue from interfering with subsequent tungsten deposition.

[0006]

However, the known method has certain drawbacks. Typically, chamber cleaning is done after each wafer is processed. This reduces wafer throughput due to the time required to set up and perform a plasma cleaning step and subsequent evacuation and purging steps after each wafer is removed from the chamber. A decrease in wafer throughput causes an increase in production cost.

A further serious drawback of the known method is the disassembly of the elements in the vacuum deposition chamber when exposed to the plasma during the cleaning step. In particular, fluorine plasma attacks aluminum elements such as heater plates and causes Al
Form F. Surface AlF deposits act as a source of particles that interfere with subsequent wafer processing. Further, since AlF is an insulating material, the presence of the AlF layer on the heater plate affects the wafer processing temperature and thus the rate and uniformity of film deposition on the wafer.

One proposed solution to the above problem was to lengthen the chamber cleaning intervals. Two
If the chamber is cleaned every time 5 to 50 wafers are processed, the indirect time is shortened and the production cost is reduced. However, the delayed chamber cleaning does not solve the problems caused by plasma attack on exposed elements such as aluminum heater plates in the chamber and the consequent formation of deposits such as AlF.

A periodic cleaning method using a low temperature plasma was used. However, such a method still does not completely solve all the challenges of plasma attack. Mechanical cleaning methods (ie, shaving methods) are also used, but are generally inadequate in that they do not remove all deposits and can damage the heater plate.

Aluminum wafers were used to protect the anodized aluminum chuck surface during the etching process. However, such wafers are also susceptible to plasma attack, making them unsuitable for protecting aluminum heater plates from plasma attack during cleaning.

Accordingly, there is provided a method of cleaning an enclosed space such as a vacuum deposition chamber that reduces indirect time and avoids the formation of harmful deposits on elements within the enclosed space such as a heater plate within the vacuum deposition chamber. Is desirable.

[0012]

According to one aspect of the invention, there is provided a method of removing deposits from within a space at least partially bounded by a plasma attack surface. The method includes the steps of placing a cover comprising a plasma inert material on the surface and removing deposits, preferably by etching with a plasma. This inert cover protects the underlying surface from attack by the plasma. Being inert to the plasma, this cover can be used repeatedly. In addition, the underlying surface is protected from plasma attack, thus increasing plasma power and reducing cleaning time during plasma cleaning.

Thus, the method of the present invention allows a space such as a vacuum deposition chamber in which an aluminum heating element is located to be cleaned less frequently and in less time than known cleaning methods. The chamber throughput and thus the economics of operation are correspondingly increased.

Further provided is a method of processing a semiconductor wafer in a vacuum deposition chamber that includes a deposition and etching process that includes a novel method of removing deposits.

According to another aspect of the present invention, there is provided a coated wafer containing a plasma inert material used to remove deposits from a vacuum deposition chamber containing a heater plate after processing a semiconductor wafer. .

According to another aspect of the invention, there is provided an apparatus for processing a semiconductor wafer including a heater plate and a vacuum deposition chamber containing a coated wafer as described above.

Other objects, features and advantages of the invention will be apparent to those skilled in the art from the following detailed description. It should be understood, however, that the detailed description and individual embodiments, while indicating the preferred embodiments of the present invention, are for purposes of illustration and not limitation. Many changes and modifications within the scope of the present invention are made without departing from the spirit thereof, and the present invention includes all of them.

[0018]

The following detailed description refers to a preferred embodiment of the invention in which the space is bounded by a vacuum deposition chamber containing a heater plate, particularly an aluminum or aluminum alloy heater plate. Semiconductor wafers are processed in a vacuum deposition chamber using a variety of methods including etching processes and vapor deposition methods such as CVD. A specific CVD method involves depositing a material such as tungsten after heating the wafer.

An example of a vacuum deposition chamber particularly suitable as a subject of the practice of the present invention is Lei et al., US patent application Ser. No. 08 / 200,0.
No. 79, the contents of which are incorporated herein by reference. However, the present invention is not limited to vacuum deposition chambers or etching processes or tungsten CVD.
Its application should not be regarded as limited to protecting plasma sensitive surfaces from particular methods such as methods.

In particular, the term "vacuum processing chamber" as used herein refers to a chamber suitable for carrying out vacuum deposition processes, etching processes or other processes.

The present invention will be more readily understood by the accompanying drawings. In the drawings, all similar elements are similarly numbered.

FIG. 1 shows a specific embodiment of the cover 10 of the present invention. The cover 10 is a vacuum adhesion device 1
Eight wafers (shown in simplified form) are sized in wafer size to protect a portion of the upper surface 12 of the heater plate 14 in the vacuum deposition chamber 16. The coated wafer 10 is suitable for use, for example, after a "complete deposition" process in which the material is deposited on the entire surface of the semiconductor wafer and also on exposed portions of the heater plate 14 and other surfaces within the vacuum deposition chamber 16. Is.

A typical heater plate 14, shown in greater detail in FIG. 3, has concentric grooves 2 on its upper surface 12.
Radial groove 2 with 0, 1 or more vacuum ports 24 separated
2. Various features may be included such as holes 26 for receiving support pins 28 and guide pins to facilitate proper placement of the semiconductor wafer. One or more of these features can be protected from plasma exposure by cover 10. The heater plate 14 can have structures other than the circular structure of FIG. 3 to accommodate wafers having shapes other than circles.

The cover 10 can have a variety of shapes and configurations. For example, the cover 10 is designed to protect the entire upper surface 12 of the heater plate 14. This is accomplished by covering the size of the cover 10 only on the upper surface of the heater plate 14 or separately extending beyond the edges of the heater plate 14. Another preferred embodiment is shown in FIG. In this embodiment, the cover 10 is the upper surface 1 of the heater plate 14.
A shadow containing more than two, typically including ceramic materials
The outer periphery 19 is protected by the plate 21. This embodiment is suitable for use after the "proprietary deposition" process in which the material is deposited only on the surface of the semiconductor wafer which is not protected by the shadow plate 21. In the exclusive deposition process, the material is not deposited on a portion of the upper surface 12 of the heater plate 14, but only on other surfaces within the vacuum deposition chamber 16, such as the shadow plate 21.

Also, such a cover 10 may be in the form of a cap or other structure that is placed over the entire upper surface 12 of the heater plate 14 or a portion thereof, and the guide pin 30.
It can be shaped to adapt to protruding features such as.

In a specific embodiment, the cover 10
Is designed to cover only a portion of the upper surface 12 where the semiconductor wafer is placed during the procedure. That is, the cover 10
It is made in the form of a coated wafer having substantially the same shape and size as a semiconductor wafer. Thus, in the preferred embodiment shown in FIGS. 1 and 4-7, the cover is configured to protect only a portion of the plasmid sensitive upper surface 12 of the heater plate 14. Also, if the entire upper surface 12 of the heater plate 14 is covered by a semiconductor wafer, or if the semiconductor wafer extends beyond the edge of the heater plate 14 as in FIG. 2, the cover 10 may also cover or edge the heater plate 14. Made to extend beyond. The advantage of such a coated wafer is to place the cover 10 in the chamber 16 by cleaning the same processing means (eg, robot blade, not shown) used to place the semiconductor wafer in the vacuum deposition chamber 16. Can be used for.

Due to the specific structure of the semiconductor wafer processed in the vacuum deposition apparatus 18 and the heater plate 14 used therein, the cover 10 is substantially circular (FIG. 4).
Or one or more flats 32 (FIG. 5-6, percentages are not constant) or notches 34 (FIG. 7, percentages are not constant). The plane 32 can be relatively narrow (FIG. 5) or wide (FIG. 6) depending on the standards applicable to the semiconductor wafer to be processed. For example, JE
Since the semiconductor wafer manufactured according to the IDA (Japan) standard has a relatively narrow flat surface, the corresponding cover 10 also has a narrow flat surface.

The cover of the present invention comprises a plasma inert material used to remove deposits from the vacuum deposition chamber or other space to be cleaned. One preferred class of plasma-inert materials are ceramic materials, for example oxides or nitrides of metals such as aluminum, zirconium, cerium or lanthanum. When used to protect a portion of the heat transfer surface of a heater plate in a vacuum deposition chamber in which semiconductor wafers are processed, it is especially preferred that the material used, such as a ceramic material, be thermal shock resistant. This is because in such applications the cover is usually introduced in a high temperature environment. Typical semiconductor wafer processing temperatures are about 250-650 ° C. It is considered that the cover made of a material having a thermal shock resistance is less damaged even when it is introduced into a high temperature environment in the vacuum deposition chamber.

Also, the selected plasma-inert material used to manufacture the cover of the present invention deposits tungsten or tungsten silicide but does not react, and the deposit is removed from a space, such as a vacuum deposition chamber, afterwards. Are removed without producing particles that interfere with the deposition process of.

Particularly preferred ceramic materials useful in the present invention are aluminum oxide (Al ₂ O ₃ ) and aluminum nitride (AlN). These materials are very thermal shock resistant and additionally deposit tungsten or tungsten silicide.

In the preferred embodiment, the coated wafer of the present invention useful for protecting the vacuum deposition chamber heater plate is such that the coefficient of thermal expansion of the plasma inert material used is taken into account relative to the coefficient of thermal expansion of the semiconductor wafer. Designed to.
This ensures that the coated wafer covers the desired area at the temperature in the vacuum deposition chamber. For example, aluminum oxide and aluminum nitride have a higher coefficient of thermal expansion than silicon. That is, coated wafers made of aluminum oxide or aluminum nitride are manufactured with a slightly smaller diameter at room temperature than semiconductors made of silicon.

In another embodiment, the cover of the present invention has a composite structure. In this embodiment, the layer of second material which is not necessarily plasma-inert is coated on at least one side with the plasma-inert material used. The layer of second material is preferably entirely coated with a plasma-inert material. For example, a metal wafer is provided with a layer of plasma inert material on one or both sides to form a sandwich structure.
If the second material is not plasma inert, then that portion should not be exposed. The various layers, including the composite cover, must be formed from materials having similar coefficients of thermal expansion to ensure that the composite cover does not warp or crack.

Referring to FIG. 8A, the cover 10 has a composite structure having a core layer 36 and a coating 38 of plasma inactive material. In FIG. 8 (b), the core layer 36 of the cover 10 has a layer 40 containing a plasma inert material on each side thereof.

Covers of the present invention, such as coated wafers, are designed to make intimate contact with the plasma sensitive surface so that no space is created for the plasma to enter. For example,
The cover 10 has plasma grooves 20 and 22 and a vacuum port 2
It is preferably designed to lie flat on the heater plate 14 so that it cannot flow under the cover 10 in contact with 4. That is, a coated wafer having a flat surface 32 or notch 34 is preferably placed on the heater plate 14 such that the flat surface or notch does not expose the groove or vacuum port.

Covers of the present invention, such as coated wafers, are typically not vacuum chucked during deposit removal, but intimately contact with plasma sensitive surfaces, especially when the use removal process, ie, the plasma etching process, is performed at low pressure. Will come into contact with. However, in some cases, the cover,
In particular, the coated wafer is vacuum chucked during a subsequent seasoning step as detailed below.

In another embodiment, the cover may be in the form of a plasma sensitive surface cap. The cap may have, for example, the shape of a disc with a peripheral edge or wall that closes the concentric grooves of the heater plate, or may include other means of fitting the cap about the surface to be protected. Such caps are typically
It contacts the plasma sensitive surface only around its periphery, leaving a space between the rest of the cap and the plasma sensitive surface, but preventing plasma flow into that space.

The cover of the present invention is manufactured using conventional means suitable for the plasma inert material used. Typically, coated wafers can be formed from aluminum oxide or aluminum nitride by a variety of methods including combustion, firing, CVD or plasma spraying. For example, firing may be performed under high pressure (about 2000-4000 psi) under an inert atmosphere.
a, preferably about 2500-3500 psia) and elevated temperature (about 1700-2000 ° C.).

According to another preferred embodiment, the cover of the present invention comprises a metal layer having at least one surface in contact with the plasma sensitive surface. In the preferred embodiment, where the cover is a coated wafer used to protect a portion of the heated surface of the vacuum deposition chuck heater plate, the metal layer is a robot blade to be detected by a capacitive sensor in communication with the robot blade. It is possible to mount a coated wafer on a wafer processing means such as.

The optional metal layer has a thickness of about 100 to 5000 angstroms and is preferably formed by conventional methods such as vapor deposition. As a specific metal,
Aluminum and tungsten are mentioned. The coated wafer can be provided with an optional metal layer on one or both sides. The coated wafer preferably has a peripheral exclusion zone that is free of a metal layer extending from about 2 to 10 mm, preferably 5 mm from the edge of the wafer. This prevents plasma etching of the metal layer.

The cover of the present invention protects a plasma sensitive surface, such as the upper surface of an aluminum heater plate or a portion thereof, in a vacuum deposition chamber from the plasma etch conventionally used to remove deposits. Used. In the particular process in which the cover 10 shown in FIG. 1 is used, deposits on the exposed upper surface 12 of the heater plate 14 are removed along with other surfaces within the vacuum deposition chamber 16. In another specific process in which the cover 10 shown in FIG. 2 is used, only the shadow plate 21 and deposits on other surfaces within the vacuum deposition chamber 16 are removed. In such a process, shadow plate 21 and cover 10 are typically maintained in a spaced relationship, for example by withdrawing cover 10 on heater plate 14 from contact with shadow plate 21 at least partially. To be done.

In certain specific processes, a gas capable of reacting with the deposit to be removed is flowed into the space to be cleaned, eg, the vacuum deposition chamber. A plasma is then generated in the space while flowing gas and reacting with the deposits on the exposed surface.

The gas used in the etching process is typically a halogen gas source such as fluorine or chlorine. The gas is NF ₃ , SF ₆ , CF ₄ and C ₂ F
A fluorine gas source such as ₆ is preferred. NF ₃
Is particularly preferable. Other gases used in the plasma etching process are also expected to be useful in the present invention. Gas mixtures can also be used. An inert or non-reactive diluent gas such as argon, neon or helium can be mixed with the gas or gas mixture.

The appropriate flow rates of the gas (gas mixture) that is reactive with the deposit to be removed and the temperature and pressure in the vacuum deposition chamber or other space are among the conventional factors in which the deposit is removed. It can be easily determined by those skilled in the art in consideration of the volume and the amount of deposits to be removed. Typical process parameters are found in Chang et al., US Pat. No. 5,207,8.
No. 36, the entire disclosure of which is incorporated herein by reference.

The use of the cover of the present invention allows the use of plasmas having a wider range of power than conventionally used plasmas. About 50-2000 watts, preferably 6
Plasma powers of 00 to 2000 watts, especially 600 to 1000 watts, can be used. For example, diameter 6 "
When a vacuum deposition chamber containing a heating plate with (150 mm) is processed, the preferred plasma power is 600
Watt. If the heating plate has a diameter of 8 "(200 mm), the preferred plasma power is 1000 watts.

The high plasma power levels made possible by the present invention provide short duration plasma etching. Typically, the plasma etching step is about 10
~ 600 seconds. With a plasma power of 600 watts, the plasma etching step is performed for about 10 to 300 seconds, depending on the amount of deposits removed.

In some cases, an optional additional step of removing residues such as residual fluorine residues from the plasma etching step can be performed after the etching step. Processes that include such additional removal steps are described, for example, in Chang, US Pat. No. 5,207,836.
No.

As mentioned above, the space in which the cover of the present invention is introduced may be at a high temperature. This is especially true if the coated wafer to be used to protect the heating plate in the vacuum deposition chamber in which the semiconductor wafer is processed is the cover of the present invention. Such treatments are typically carried out at temperatures of about 400-490 ° C. and about 1-100 Torr. The use of materials that are heat shock resistant minimizes damage to the cover due to sudden changes in temperature. Sufficient to raise the temperature of the material to prevent thermal shock damage to the cover in space and on plasma sensitive surfaces (otherwise away from direct contact) to further eliminate damage due to thermal shock It is preferable to hold the cover for a long time. After the cover has been heated in this way, it is placed in contact with the plasma sensitive surface.

For example, the coated wafer is introduced into the vacuum deposition chamber and is about 0.005 to 0.1 inches, preferably about 0.08 inches above the heat transfer surface of the heater plate to be protected.
It is maintained at a height of an inch (2 mm) (by conventional means such as a robot arm or support pin). After about 20-30 seconds, the temperature of the coated wafer slowly increased to a level such that it could be safely placed on the heater plate without substantial risk of thermal shock damage to the coated wafer.

It is also possible to preheat the cover before introducing it into the space having the plasma-sensitive surface to be protected. In this embodiment, the cover can be manufactured from a material having low thermal shock resistance.

A specific method showing the above-mentioned various features is as follows.
This is explained in the flow sheet of FIG.

The cover of the present invention can be used as part of a method of processing semiconductor wafers in a vacuum deposition chamber that includes a cleaning step after one or more wafer processing steps. For example, the semiconductor processing method can be a deposition process or an etching process. That is,
The semiconductor wafer can be subjected to deposition or etching, such as chemical vapor deposition, and then removed from the vacuum deposition chamber. One or more semiconductor wafers are preferably subsequently processed in a vacuum deposition chamber in a similar manner. A total of 25 to 50 semiconductor wafers are preferably so treated. After processing the semiconductor wafer, the deposits created during the deposition or etching process are removed in the manner described above. The coated wafer is introduced into a vacuum deposition chamber and placed on the heat transfer surface of a heater plate within the chamber. The deposit in the chamber is then removed by plasma etching. Residues such as fluorine residues are also subsequently removed. The semiconductor wafer processing method can then be repeated.

In the preferred embodiment of the deposition process described above, the vacuum deposition chamber is seasoned following the plasma etching step. Seasoning
This is done by introducing into the chamber a predetermined trace amount of a material such as tungsten or tungsten silicide that accumulates in the chamber during processing. The seasoning step ensures a more uniform semiconductor wafer processing environment. Seasoning is typically done in the presence of the cover, but can also be done after removing the cover from the chamber.

Seasoning can be performed in one or more steps. For example, if a semiconductor wafer is processed using full coverage deposition as described above, seasoning can be performed using SiH ₄ reduction of WF ₆ (used in the nucleation step of tungsten deposition on wafers). Step). The seasoning step deposits a thin layer of tungsten, eg, about 800 angstroms, on the top surface of the coated wafer and the heater plate not protected by the coated wafer and the surrounding surface in the vacuum deposition chamber. If the semiconductor wafer is processed using only the deposition process described above, the seasoning is preferably done in two steps. The first step uses SiH ₄ reduction of WF ₆ as in the seasoning process described above. This results in a thin layer of tungsten (typically about 800 Angstroms) that is placed on the shadow ceramic and heater plates and adheres well to the coated wafer on which the shadow plate rests. However, shadow plates typically require additional seasoning. That is, the second seasoning step uses H ₂ reduction of WF ₆ for a time sufficient to form a thin layer of tungsten on the coated wafer and shadow plate. In the concrete seasoning process, the second step is carried out for about 120 seconds, and about 12,
This results in a tungsten film having a thickness of 000 Å. Without the first seasoning step, the tungsten does not adhere well to the shadow plate.

By way of non-limiting example,
The present invention will be described more specifically.

Example 1 Cover A. Aluminum Nitride (AlN) Coated Wafer Aluminum Nitride Powder (Purity 99.9%, Burning Acid that Can Be Etched by Plasma, eg Y ₂ O
₃ not included; made from NGK) is fired in an inert atmosphere at high pressure and high temperature to form a plate having a density of about 3.25 g / cm ³ . A wafer (disk-shaped) is cut from the plate and ground, preferably by double-sided grinding, to the desired thickness depending on the wafer diameter used. For a diameter of about 200 mm, the thickness is preferably about 1.0 to 1.25 mm. Diameter about 1
For 50 mm, the thickness is preferably about 0.75 to 1.00 mm. The periphery of the wafer is ground, optionally with bevels and / or planes or notches.

When used with a silicon wafer having a diameter of 200 mm, an aluminum nitride coated wafer has a diameter of 200 mm.
It is preferred to have mm ± 0.2 mm.

The first aluminum nitride plate can also be manufactured by chemical vapor deposition of an AlN film, but such a process is more costly than the firing process described above.

B. Aluminum oxide (Al ₂ O ₃ ) coated wafer Aluminum oxide (preferably at least 99% pure)
Are formed into a plate shape and burned. The plate is then ground, preferably by double-sided grinding, to approximately a wafer shape having 0.75 to 1.25 mm depending on the diameter of the wafer. The periphery of the wafer is ground, and bevel and / or
Or provide a plane or notch.

When used with a silicon wafer having a diameter of 200 mm, the aluminum oxide coated wafer preferably has a diameter of 199.5 mm ± 0.1 mm in view of the high coefficient of thermal expansion of aluminum oxide relative to silicon.

Example 2 Deposition Process Including Cleaning Step The following process is performed using a Precision 5000 xZ vacuum deposition equipment from Applied Materials, Inc. (Santa Clara, Calif.). Centura of Applied Materials
Other commercially available devices such as xZ can also be used.

A. The deposited silicon wafer is introduced into the vacuum deposition chamber of a Precision 5000 xZ apparatus and heated to a selected processing temperature of 475 ° C. After pre-nucleation with conventional WF ₆ and SiH ₄ , chamber purge, pressurization and stabilization of the wafer on the heater plate, WF ₆ under 90 Torr pressure (flow rate 95 scc
m) is used for tungsten deposition. Then, the wafer is taken out, and the chamber is purged and exhausted (Ar / N
₂ / H ₂ purge) and repeat the deposition process until 25 silicon wafers have been processed.

B. NF ₃ Plasma Cleaning The aluminum nitride coated wafer is introduced into a vacuum deposition chamber with a heater plate maintained at a selected processing temperature of 475 ° C. and heated for 23 seconds. Simultaneously or subsequently, NF ₃ is introduced into the chamber at 150 sccm and a base pressure of 300 mT. After heating for 23 seconds, the coated wafer is placed on the heater plate so that the area covered by the silicon wafer is protected. Once the coated wafer is in place, a 600 watt plasma is generated, an NF ₃ plasma etch is performed for 227.5 seconds and the plasma power is reduced to 200 watts for 225 seconds. Purge / exhaust 2
Cycle (Ar / N ₂ / H ₂ purge 3 per cycle 3
After 0 seconds, evacuation 3 seconds), the chamber pressure is lowered to _4.5 Torr, and the chamber is seasoned for 30 seconds by introducing WF ₆ (10 sccm) and SiH ₄ (5 sccm) into the chamber. Then, the chamber pressure is returned to atmospheric pressure. After 3 cycles of purge / evacuation (3 seconds Ar / N ₂ / H ₂ purge, 3 seconds evacuation per cycle), the deposition procedure is repeated.

That is, the vacuum deposition apparatus including the vacuum deposition chamber having the heater plate together with the cover of the present invention enables an increase in the throughput of semiconductor wafers, thereby increasing the economical efficiency of the conventional apparatus.

[0064]

Since the present invention is constructed as described above, it shortens the indirect time and prevents the formation of harmful deposits on elements in enclosed spaces such as heater plates in vacuum deposition chambers. A method of cleaning enclosed spaces such as vacuum deposition chambers to avoid can be provided.

[Brief description of drawings]

1 is a cross-sectional view of an embodiment of a cover of the present invention disposed on a heater plate within a vacuum deposition chamber of a vacuum deposition apparatus.

FIG. 2 is a cross-sectional view of an embodiment of a cover of the present invention disposed on a heater plate in a vacuum deposition chamber of a vacuum deposition apparatus and partially protected by a shadow plate.

FIG. 3 is a plan view of an exemplary vacuum deposition chamber heater plate that is advantageously protected with the cover of the present invention.

FIG. 4 is a plan view of a specific embodiment of the cover of the present invention in a protective position on various heater plates.

FIG. 5 is a plan view of a specific embodiment of the cover of the present invention in a protective position on various heater plates.

FIG. 6 is a plan view of a specific embodiment of the cover of the present invention in a protective position on various heater plates.

FIG. 7 is a plan view of a specific embodiment of the cover of the present invention in a protective position on various heater plates.

FIG. 8 is a cross-sectional view of another cover of the present invention having a composite structure.

FIG. 9 is a flow sheet showing the cleaning method of the present invention.

[Explanation of symbols]

10 ... Cover, 12 ... Upper surface of heater plate, 14 ... Heater plate, 16 ... Vacuum deposition chamber, 18 ... Vacuum deposition device, 19 ... Perimeter, 20 ... Groove, 21 ... Shadow plate,
22 ... Groove, 24 ... Vacuum port, 26 ... Hole, 28 ... Support pin,
30 ... Guide pin, 32 ... Plane, 34 ... Notch, 36 ... Core layer, 38 ... Coating, 40 ... Layer containing plasma inactive material.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication location H01L 21/304 341 D // C30B 33/12 7202-4G (72) Inventor Lawrence Chan-Ray Ray Country Crab Drive, 1950 (72), Milpitas, California 95035, California, USA Inventor Sasson Someku, USA 94022, Los Altos Hills, Moodie Road 25625

Claims (28)

[Claims] 1. A deposit from a space at least partially bounded by a surface attacked by a plasma.
(a) placing a cover containing the plasma-inert material on the surface (placi).
ng), and (b) removing the deposit by plasma treatment. 2. The method of claim 1, wherein the material is a ceramic material. 3. The method of claim 2, wherein the material is selected from the group consisting of metal oxides and metal nitrides. 4. The ceramic material is selected from the group consisting of aluminum oxide and aluminum nitride.
The described method. 5. The method of claim 1, wherein the material is thermal shock resistant. 6. The method of claim 1, wherein the space is a vacuum deposition chamber for processing semiconductor wafers. 7. The method of claim 6, wherein the surface is at least a portion of a heating surface of a heater plate. 8. The method of claim 7, wherein the surface is a portion of the surface of the heater plate overlaid with the semiconductor wafer during processing in the vacuum deposition chamber. 9. The method of claim 8, wherein the cover is a wafer shaped substantially similar to the shape of the semiconductor wafer. 10. The method of claim 1, wherein at least a portion of the cover in contact with the surface is coated with a metal layer. 11. The method of claim 6, further comprising depositing a material selected from the group consisting of tungsten and tungsten silicide on a wafer disposed on the surface to form the deposit. Method. 12. The step (b) wherein the deposit comprises (i) flowing a gas capable of reacting with the deposit into the space, and (ii) flowing the gas and reacting with the deposit. The method of claim 1, wherein said method is removed by a plasma etching process including the step of generating said plasma in said space. 13. The method of claim 12, wherein the gas is a halogen gas source. 14. The gas is NF ₃ , SF ₆ , CF ₄
The method according to claim 13, wherein the method is selected from the group consisting of C ₂ F ₆ and C ₂ F ₆ . 15. Step (b) is performed for a time in the range of about 10 to about 600 seconds and the plasma power is about 50 to about 20 as the fluorine gas source flows through the space.
13. The method of claim 12, varying within the range of 00 watts. 16. The material on the surface for a time sufficient to heat the space and raise the temperature of the material so as to reduce the risk of thermal shock damage before placing the material on the surface. The method of claim 1, wherein the material is held in a space. 17. A method of removing tungsten or tungsten silicide from a vacuum deposition chamber including a heater plate after processing a semiconductor wafer, the method comprising: (a) coating a wafer containing a plasma-inert ceramic material onto the heater plate; Covering at least part of the heating surface,
(B) flowing a fluorine gas source capable of reacting with the deposit into the vacuum deposition chamber; and (c) flowing the fluorine gas source and reacting with the deposit while the plasma is present in the vacuum deposition chamber. A step of igniting. 18. A method of removing tungsten or tungsten silicide from a heated vacuum deposition chamber including a heater plate after processing a semiconductor wafer, comprising: (a) a ceramic material selected from the group consisting of aluminum oxide and aluminum nitride. Introducing the coated wafer into the vacuum deposition chamber, (b) the vacuum above the heated surface of the heater plate for a time sufficient to raise the temperature of the coated wafer such that the risk of thermal shock damage is reduced. Holding the coated wafer in the deposition chamber, (c) overlaying the coated wafer on at least a portion of the heat transfer surface of the heater plate, (d) pouring NF ₃ into the vacuum deposition chamber, (e) ) plasma in the vacuum deposition chamber wherein the NF ₃ was flowed and while reacting with said deposits Comprising the step, of generating. 19. A method of processing a semiconductor wafer in a vacuum processing chamber including a heater plate, comprising: (a) processing a semiconductor material in the vacuum processing chamber; and (b) processing the semiconductor material from the vacuum processing chamber. Removing the wafer; and (c) depositing deposits formed during the process from the vacuum processing chamber, and (i) covering the wafer with a plasma inactive material on at least a portion of the heating surface of the heater plate. Covering step, (ii) flowing a gas capable of reacting with the deposit into the vacuum processing chamber, and (iii) flowing the gas and reacting the plasma with the plasma in the vacuum processing chamber while reacting with the deposit. Generating, and removing by a process that includes. 20. The method of claim 19, wherein in step (a) the semiconductor material is processed by etching. 21. The method of claim 19, wherein in step (a) the semiconductor material is processed by chemical vapor deposition. 22. The method of claim 19, wherein steps (a) and (b) are continuously repeated from about 25 to about 50 times before step (c) is performed. 23. Seasoning the vacuum processing chamber
20. The method further comprising (seasoning) step (d).
The described method. 24. A coated wafer comprising a plasma inert material used to remove deposits when used in a method of removing deposits from a vacuum processing chamber. 25. The coated wafer of claim 24, comprising a material selected from the group consisting of aluminum oxide and aluminum nitride. 26. The coated wafer of claim 24, wherein the coated wafer has a shape substantially similar to the shape of the semiconductor wafer. 27. The coated wafer of claim 24, wherein at least one side thereof is coated with a metal layer. 28. An apparatus for processing a semiconductor wafer comprising: (a) a vacuum processing chamber containing a heater plate, and (b) a coated wafer containing a plasma inert material.